Can you set velocimacro.context.localscope = true or is it important for your system to be able to #set global stuff from within macros?
On Mon, Apr 30, 2012 at 10:50 AM, Boris Partensky <boris.parten...@gmail.com> wrote: > Thanks Nathan, I think I do get the whole scoping idea, but my > understanding was that one of the reasons to turn all scoping off by > default (and have those properties to begin with) was to provide > backward compatibility - as in: I upgrade to 1.7 and then I start > turning on all those nice bells and whistles and use scopes and what > not. Not so seems like? I also find somewhat strange that a a formal > argument to a macro takes precedence and overwrites a global variable > with the same name. How would one go about upgrading existing systems? > We have roughly 1900 macros, big chunk of those are nested... Maybe I > am misunderstanding something, but this issue makes it almost > impossible to upgrade (at least for us). > > > Thanks > Boris > > On Mon, Apr 30, 2012 at 12:55 PM, Nathan Bubna <nbu...@gmail.com> wrote: >> Yeah, it was intended, and part of an overall move toward >> fixing/simplifying Velocity's variable scoping, avoiding the >> complexities and costs (performance, yes, but mostly time/brainpower >> for users and devs alike) of more programming language type behavior. >> Velocity has long aspired to be a straightfoward template engine and >> avoid being a complete scripting language. (Implicit) variable >> scoping, as seen in 1.5, was seen as a necessary compromise toward the >> latter; after all, one big fat namespace is always unmanageable, >> right? Well, there's ways to make that easy to manage. :) Let's call >> it "optional, provided, explicit scoping", explicit because you don't >> have to grok the contextual scope to understand a reference, optional >> because you can ignore it, and provided because Velocity does the work >> of choosing "prefixes" and creating/destroying the scopes (as any >> implicit scoping system does). So everything is becoming globally >> scoped, but it is now trivial to turn on automatic, explicit scopes or >> namespaces that you can use when you don't want things to live in the >> global scope. >> >> Here's an example... Do you use $velocityCount to get an index of >> sorts inside of #foreach directives? Well, that's an example of mixed >> implicit/explicit namespacing that gets messy when you nest >> #foreach's, with no good way to get the parent's count and >> unwieldiness when you want to add $velocityIndex, $velocityHasNext and >> so on. Now, we automatically manage a $foreach var that not only has >> a 'count' property, but an 'index', 'hasNext', 'parent', and so on >> (see >> http://velocity.apache.org/engine/devel/apidocs/org/apache/velocity/runtime/directive/ForeachScope.html). >> It also, of course, accepts any property you want to set on it (like >> any map). This makes templates instantly understandable, making >> debugging much better. You always know exactly what you are referring >> to, and so does anyone else reading the template. >> >> #foreach is the only 'content directive' that has its explicit scope >> automatically turned on, but all content containing directives >> (including custom body macros) can have their own explicit, >> auto-managed scope, named after themselves. for example, you can flip >> the macro scope on: >> >> macro.provide.scope.control = true >> >> and do: >> >> #macro( outer $arg ) >> #set( $macro.arg = $arg ) >> #inner( 'inner' ) >> #end >> #macro( inner $arg ) >> #set( $macro.arg = $arg) >> inner: $macro.arg >> #if( $macro.parent )outer: $macro.parent.arg#end >> #end >> >> #outer( 'outer' ) >> #inner( 'just inner' ) >> >> and get >> >> inner: inner >> outer: outer >> inner: just inner >> >> Hope this helps... >> >> In any case, there was plenty of thought and discussion that went into >> this change. Search http://velocity.markmail.org for 'scope' and you >> should find more on this. >> >> On Mon, Apr 30, 2012 at 8:49 AM, Boris Partensky >> <boris.parten...@gmail.com> wrote: >>> Hello, while going through the upgrade I noticed an incompatible >>> behavior during nested macro evaluation. Looks like in 1.7 (all >>> default properties) child macro has access to variables set in parent >>> macro scope (and those take precedence over globals), and 1.5 sees >>> globals. In the following example, in 1.5 unit test the following >>> template will evaluate to "globalvar", and in 1.7 - to >>> "outermacroparam". Is this expected behavior? >>> >>> >>> 1.5 test case >>> >>> >>> public void testVelocityNestedMacroScope() throws Exception >>> { >>> VelocityEngine ve = new VelocityEngine(); >>> >>> ve.init(); >>> >>> String template = "#macro(outerMacro $arg1)"+ >>> "#innerMacro('blah')"+ >>> "#end"+ >>> "#macro(innerMacro $arg2)$arg1#end"+ >>> >>> "#set($arg1='globalval')#outerMacro('outermacroparam')"; >>> StringWriter eval = new StringWriter(); >>> boolean b = ve.evaluate(new VelocityContext(), eval, "foo", >>> template); >>> assertEquals(eval.toString(), "globalval", eval.toString()); >>> >>> } >>> >>> 1.7 test case >>> >>> >>> public void testVelocityNestedMacroScope() >>> { >>> String template = "#macro(outerMacro $arg1)"+ >>> "#innerMacro('blah')"+ >>> "#end"+ >>> "#macro(innerMacro $arg2)$arg1#end"+ >>> >>> "#set($arg1='globalvar')#outerMacro('outermacroparam')"; >>> String eval = evaluate(template); >>> assertEquals(eval, "outermacroparam", eval); >>> >>> } >>> >>> --------------------------------------------------------------------- >>> To unsubscribe, e-mail: user-unsubscr...@velocity.apache.org >>> For additional commands, e-mail: user-h...@velocity.apache.org >>> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: user-unsubscr...@velocity.apache.org >> For additional commands, e-mail: user-h...@velocity.apache.org >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: user-unsubscr...@velocity.apache.org > For additional commands, e-mail: user-h...@velocity.apache.org > --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@velocity.apache.org For additional commands, e-mail: user-h...@velocity.apache.org
